Air sampling device and method

ABSTRACT

A lightweight, economical, mass-producible, reusable airfoil can be deployed in an airspace while in or attached to any moving vehicle for the purpose of collecting air samples. A frame has an airfoil shape that provides pressure differentials that preferentially direct particulates and contaminants of differing size and mass to different areas of an absorbent media attached or integral to the frame. The absorbent media are readily detachable from the frame for sanitary and efficient transfer to facilities where the samples can be analyzed.

This application is a continuation application of and claims priorityfrom U.S. application Ser. No. 10/601,302 filed Jun. 6, 2003 andincorporates by reference the '302 application as if it were fullyprinted herein. U.S. application Ser. No. 10/601,302 claimed priorityfrom provisional patent application No. 60/387,228 filed Jun. 7, 2002.

FIELD OF INVENTION

This invention pertains to the field of air sampling devices, morespecifically, an air sampler in the general shape of an airfoil and amethod for sampling air using the airfoil shaped sampler.

BACKGROUND

The collection of statistically significant quantities of particulatesand contaminants of interest in atmospheric analysis typically requireshigh rates of airflow. Electro-mechanical air-moving devices such aspumps, fans, and blowers force air over devices such as filters andabsorbents in order to provide the required airflow in typical samplingapplications. Such active air-moving devices are generally costly,noisy, and heavy, and require a power source.

A need exists for a small lightweight particulate air sampler designedfor use on the earth's surface as well as on vehicles. A need exists fora small lightweight air sampling device for detection of airbornechemicals particulate and contaminants at low levels of concentration.Military, homeland defense and other demands exists for an inexpensivevehicle mounted air sampler.

SUMMARY OF THE INVENTION

Applicants provide an air sampling device comprised of a frame and mediamembers, the media members for engaging the frame, and the device forpassing through the air to collect particulates when the air passesthrough the media members. More specifically, Applicants provide a framefor engaging media members, the frame constructed in the shape of one ormore airfoils, having leading and trailing edges.

The airfoil shaped apparatus is effective, lightweight, inexpensive, andcapable of mass production. It mounts to any moving carrier, andcollects air samples as the carrier moves through the air.

The airfoil shaped device produces differential air pressures and airvelocities over its surface according to the application of Bernoulli'slaw. Differential pressure provides for particulate separation accordingto mass and size of the individual particles, thus offering a built-inpassive filtration capability.

Users of Applicants' airfoil shaped air sampler may use any vehicle,including but not limited to, a lightweight, unmanned, radio-controlledairborne vehicle, including a glider, for deploying the air sampler.Such use provides an efficient, lightweight, and highly mobile platformfor Applicants' airfoil shaped air sampler.

The present invention includes a frame constructed in the shape of anairfoil. At the leading and trailing edges the airfoil typically hasgaps of varying and variable dimension through which air can pass whenthe frame is suspended in the airflow in or around the moving carrier.The airfoil shape creates differential pressures and velocities on thetop and bottom airfoil surfaces and the leading edge and trailing edge,an effect being that particulates of different size and mass tend to beseparated into different air streams over, under, and through theairfoil. The airfoil itself can be constructed, at least in part, of anabsorbent media which is sized to pick up particulate matter, or theairfoil may include a frame upon which an absorbent media will rest, theabsorbent media for retention of particulate particles as the carrierpasses through the air.

The earth sampler device of Applicants' present invention may also bedesigned to sample airborne chemicals. That is, airborne particulatesand/or chemicals may be sampled with Applicants' present device. Indeed,Applicants' present invention may include a second airfoil shape throughwhich a pressure differential can drive an air sample across anabsorbent carbon based bed, which would pick up some chemicals in theair.

Applicants' present invention may include a means to mount the airfoildevice on a moveable vehicle such as a small, lightweight, unmanned,airborne “drone,” a ground vehicle or a water craft. The means to mountmay include a power server on gears to fold the air sampling device froma position in the air stream to position out of the air stream.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates Applicants' novel air sampler in perspective viewshowing the relative direction of air travel.

FIG. 2 is a side cross-sectional view of the air sampler showing the topand bottom airfoil sections as well as the frame and absorbent materialthat may be located between the airfoil sections.

FIG. 3 illustrates a side perspective view of Applicants' novel airsampler without the absorbent media thereon.

FIG. 4 is a front elevational view of the air sampler as illustrated inFIG. 3.

FIG. 5 is a top elevational view of the air sampler as illustrated inFIGS. 3 and 4.

FIG. 6 is a cross-sectional side view of the air sampler of Applicants'present invention showing the frame and the absorbent material placedthereon.

FIG. 7 is an exploded view of the air sampler without the absorbentmedia engaged with the frame thereof.

FIG. 8A is an assembled view of an alternate preferred embodiment ofApplicants' novel air sampler, which embodiment includes a secondairfoil.

FIG. 8B is a top elevational cutaway cross-sectional view of theembodiment of the air sampler illustrated in FIG. 8A.

FIG. 8C is an exploded view in perspective of the embodiment ofApplicants' air sampler illustrated in FIG. 8A.

FIGS. 9A and 9B illustrate top elevational cutaway views of the airsampler illustrated in FIG. 8A mounted to a fuselage of an aircraft androtatable between in a closed position (FIG. 9A) and a use position(FIG. 9B).

FIG. 10 is a front elevational view of an aircraft with an air samplerrigidly attached.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 through 7 illustrate Applicants' novel air sampler (10). Airsampler (10) may include a frame (12) at least a portion of whichengages an absorbent filter media (13). Frame (12) typically iscomprised of at least one airfoil member, the figure here showing anembodiment including an upper airfoil member (14) and a lower airfoilmember (16). The members typically have a multiplicity of through holes(14A and 16A), and may be spaced apart so as to define a leading edgegap (20) and a trailing edge gap (22). End plates (18A and 18B) providesupport and location for the upper and lower airfoil members. Betweenthe upper and lower airfoil members, which are typically provided asillustrated in the cross-section of FIG. 2, and are bowed away from eachother, there may be a pleated or cup shaped frame member (17). The cupshaped frame member may have an open end (17A) facing the leading edgegap (20) and a closed end (17B) opposite the open end, typicallycomprising a longitudinal axis that lies on the chord between theleading edge and the trailing edge of the upper and lower airfoilmembers. The pleat or cup shaped frame member (17) typically attaches toone end plate and may notch into the other (see FIG. 8C) end plate. Thepleat or cup shaped member may attach to the inner sides (17G and 17H)of the airfoils. The frame may be made of Duraform® or of any othersuitable material and made by SLS (Selected Layer Scintering) or by anysuitable method. The frame, including the upper and lower airfoil, theend plates, and the pleated cup shaped frame members may be injectionmolded from a plastic or other suitable material. Absorbent filter media(13) may be any suitable absorbent media such as Electret™ filters from3M.

The air sampling device is typically small, in chord about 3.5 inchesfrom leading edge to trailing edge and 1.3 inches in thickness (asmeasured between the upper and lower airfoils at the maximum point ofseparation). Chord range is 1.0 to 12.0 inches (preferred) and thicknessrange is 0.5 to 6.0 inches (preferred). The maximum width as measuredacross end plates (18A and 18B) is preferably about 1.5 inches(preferred range 0.5 to 3.0 inches) and the leading edges of the cupshaped frame member (17E and 17F) may be spaced apart from the adjacentairfoil by, preferably 0.25 inches (preferred range 0.1 to 1.0 inches).The preferred width of open end (17A) is about 0.5 inches (preferredrange 0.1 to 1.0 inches). This is equal, in this embodiment, to thewidth of the leading edge gap and the trailing edge gap. The length ofthe inlet (I) defined by the leading edge gap is typically about 1.5inches. Note that size of inlet (I) is typically about the same asoutlet (O) defined by trailing edge gap (22).

Air flows through airfoil surface filters and inside and through thepleated or cup shaped frame member. The cup shaped frame memberincreases the surface area of the absorbent media that is exposed to theflowing air and tends to collect the particles of highest mass in thecenter pleat. Thus, the airfoil filter tends to preferentially collectparticles separated by mass.

Applicants' novel air sampler (10) works without a pump or a fan. Air ispushed through the filter media by the force of air entering the inlet,and air is pulled through the filter media by the pressure differentialthat forms across the top and bottom of the upper and lower airfoilmembers as the airfoil moves through the air. The use of anelectrostatic filter media provides a more efficient collection ofparticulates. Further, the general aerodynamic shape provides areduction of drag. The lower pressure zones on the airfoil surfacesenhance flow through the filter. The airflow will also separateparticulate deposition on absorbent media according to the size and massof the particles. Computer testing of a model built according todimensions set forth above yielded, at a speed of approximately 30 mph,400 liters per minute sample volume.

FIGS. 8A, 8B and 8C illustrate a preferred alternate embodiment ofApplicants' air sampler (10). In this embodiment, it is seen that asecond airfoil (21) is provided, which second airfoil includes a frameor housing (22) having a curved airfoil surface (22A) thereof. Thissecond airfoil may be used to provide sampling for airborne chemicalcustom contaminates whereas the first airfoil defined by frame 12 mayuse an absorbent filter designed to physically trap airborne particles.A port (24) is provided in the housing which port will open up to thecurved airfoil surface (22A) at perforations (24A). A chemical filteringassembly (26) is located in the port (24) usually engaged with the wallsthereof by a retaining ring (26A) which retains a first screen (26B). Asorbent bed (26C) may be sandwiched between first screen (26B) and asecond screen (26D), the entire assembly held by the retaining ringagainst the walls defined in perforations (24A). Molding (29A) pressfits into grooves (29B).

When the second airfoil is fastened, as with fasteners (28), to an endplate, as here in end plate (18A), it can been seen that air passingthrough inlet (I) can be drawn through port (24) by the low pressurecreated when air flows over curved surface (22A), the air passing fromthe interior defined by the upper and lower airfoil through the port andthrough the filtering assembly. Sorbent bed (26C) may be made ofCarboxen™, an activated charcoal. Carboxen is available from ScientificInstrument Services, Inc.

FIGS. 9A and 9B illustrate a method use of an air sampling device (10)as part of a system including an aircraft (30) having fuselage walls(32) and including a plate (34) for engaging the fuselage walls, whichplate (34) may be mounted on an axle (36). The axle (36) may be drivenby a servo (38). The fuselage may include walls defining a cavity (40)which would be dimensioned to enclose the air sampling device.Activation of the servo may cause the plate to rotate and move the airsampler from a retracted position within the fuselage as illustrated inFIG. 9A to an extended position in the air stream as illustrated in FIG.9B.

FIG. 10 illustrates an aircraft (AC) here a small, unmanned radiocontrolled drone including an air sampling system. The air samplingsystem includes Applicants' air sampling device (10) rigidly mounted tothe fuselage on a bracket (52). The bracket positions the air samplingdevice in the air stream, here below the underside of the fuselage andthus outside the influence of the main wings and the tail of theaircraft.

Although the invention has been described with reference to specificembodiments, this description is not meant to be construed in a limitedsense. Various modifications of the disclosed embodiments, as well asalternative embodiments of the inventions will become apparent topersons skilled in the art upon the reference to the description of theinvention. It is, therefore, contemplated that the appended claims willcover such modifications that fall within the scope of the invention.

1. (canceled)
 2. (canceled)
 3. (canceled)
 4. (canceled)
 5. (canceled) 6.A device for sampling air, the device comprising: an at least partiallyairfoil shaped frame, the frame including top and bottom opposingsurfaces each of the surfaces defining a leading edge and a trailingedge, wherein a part of the frame defines an interior space between thetop and bottom opposing surfaces and a part of the frame occupies atleast a part of said interior space; and a pleated absorbent filtermedia for engaging the frame, the filter media being capable ofabsorbing particulate matter from an airstream.
 7. The device of claim 6wherein the absorbent filter media is electrostatically charged.
 8. Thedevice of claim 6 wherein the frame defines an opening adjacent theleading edge and adjacent the trailing edge.
 9. The device of claim 8wherein the shape of the opening adjacent its leading edge is optimizedsuch that the average velocity of the air in the opening issubstantially equal to the average velocity of the free air stream whenthere is relative motion of the frame with respect to the air.
 10. Thedevice of claim 6 wherein the longest dimension of the frame is between1.0 and 12.0 inches.
 11. The device of claim 6 wherein the total weightof the frame and absorbent material is less than about 5.0 ounces. 12.The device of claim 6 wherein the frame is formed by an injectionmolding.
 13. The device of claim 6 wherein the frame is formed at leastpartially from one of the following materials: plastic, nylon, carbonfiber, or a composite.
 14. A device for sampling air, the devicecomprising: an at least partially airfoil shaped frame, the frameincluding top and bottom opposing surfaces each of the surfaces defininga leading edge and a trailing edge, wherein a part of the frame definesan interior space between the top and bottom opposing surfaces and apart of the frame occupies at least a part of said interior space, theframe further including at least one end plate for holding the top andbottom opposing surfaces in spaced apart relation; and an absorbentfilter media for engaging the frame, the filter media being capable ofabsorbing particulate matter from an airstream.
 15. A device forsampling air, the device comprising: an at least partially airfoilshaped frame; an absorbent filter media for engaging the frame, thefilter media being capable of absorbing particulate matter from anairstream; and a vehicle being capable of moving through an airstreamand being capable of engaging the frame, the frame adapted to include amounting plate for rotably mounting the frame with respect to thevehicle such that the frame can be moved between a use position in theairstream a stored position out of the airstream.
 16. The device ofclaim 6 further including a vehicle to propel the frame through the airand a bracket to mount the frame to the vehicle.
 17. (canceled) 18.(canceled)
 19. (canceled)
 20. (canceled)
 21. (canceled)